This mine, one of the gassiest and most troubled in the state, is ironically also a good case in point as to how about go about introducing change to get better results.

Illawarra Metallurgical Coal parent company South32 CEO Graham Kerr said there was still work to do to overcome challenges at some of its operations, including the Appin and nearby Dendrobium longwall mines.

"At Illawarra Metallurgical Coal we are re-establishing minimum performance criteria and implementing work practices to improve longwall and development performance," he said.

"We believe these initiatives will enable production rates to return to historical levels."

Improved longwall performance at Appin in the December quarter has underpinned a 7% increase to its prior estimate for FY2019 to 6.5Mt.

Illawarra Metallurgical coal has reduced first half operating costs at its mines from US$149 per tonne in 2017 to $87/t for the six months to December 2018.

The company reached agreement with employees covered by the Dendrobium Mine Trades and Operators Enterprise Agreement during the December quarter, having previously reached agreement with the Dendrobium and Appin Deputies.

"We continue to renegotiate the remaining labour agreements at Illawarra Metallurgical Coal and this process is being closely managed," the company said.

Hogsback reckons it is going to take a lot of work to get underground mining in NSW competitive again but the industry is up for the challenge.